NASA's MESSENGER space craft is beaming back pictures of the planet Mercury that reveal a side of the planet we've never seen before--including a huge impact crater and remnants of volcanic activity, according to Space.com.

The craft is the first to visit Mercury in more than 30 years, and is going a long way toward demonstrating that the diminutive planet isn't as much like our own moon as we thought it was.

Among the craft's findings are that Mercury's crust was largely created through volcanism, as past eruptions spewed lava which later dried, the report said. The impact crater, meanwhile, is more than 430 miles in diameter--roughly the distance from Boston to D.C., as the article points out--and was probably formed about 3.9 billion years ago in the early stages of our solar system.